Help calculating energy quantities using spectroscopic constants?

[oltreuomo]

Hi,

I'm a new AE Ph.D. student in the field of supersonic mixing and combustion, currently making preparations for ordering equipment necessary to perform Filtered Rayleigh Scattering measurements in our tunnel.

At this point, I am implementing a model for predicting the shape of the absorption spectrum of the iodine notch filter used in the method for different filter lengths and iodine number densities. However, as I have absolutely no background in spectroscopy or quantum mechanics, understanding and implementing the model has been a bit of a bumpy road, though I believe I am nearly finished.

The point where I am stuck now is in adding the contribution of the hyperfine splitting, as I don't understand how to calculate a few of the relevant parameters. A snippet of the text (Forkey, 1997) can be seen here, which shows the values which I need to calculate. This is an excerpt of the paper which supplies spectroscopic constants that I have available to me. Of course, I also have the relevant low and high rotational and vibrational quantum numbers for each rovibrational transition being considered. I've attempted to calculate G(v'), E_r(v', J') and E(v') using the (low order, it seems) estimations found here (pdf warning), though I wasn't having any luck.

If anyone could help me understand how to calculate the required values using these constants, or point me to a good source which would explain it, I'd really appreciate it. Thanks in advance.

 

[eljose79]

Hello,

I am a fellow scientist in the field of supersonic mixing and combustion, and I am familiar with the Filtered Rayleigh Scattering method. I can understand how challenging it must be to implement a model for predicting the shape of the absorption spectrum without a background in spectroscopy or quantum mechanics.

Firstly, I would recommend reaching out to a colleague or professor who has expertise in spectroscopy or quantum mechanics for guidance on calculating the parameters needed for the hyperfine splitting contribution. They may be able to provide a more in-depth explanation and assist you in your calculations.

In addition, there are some resources that may be helpful in understanding the calculations. The paper by Forkey (1997) that you mentioned is a good starting point, as it provides spectroscopic constants and equations for calculating the hyperfine splitting contribution. You may also find the textbook "Molecular Spectroscopy" by Banwell and McCash helpful in understanding the theory and equations behind spectroscopy.

Another resource that may be useful is the National Institute of Standards and Technology (NIST) database, which provides spectroscopic data and calculators for various molecules. You can search for the specific molecule and transitions you are studying and use the calculators to determine the parameters needed for your calculations.

I hope these resources will be helpful in your research. Best of luck with your measurements and calculations!